FILE – This photo provided by the Santa Cruz County Police Department in Nogales, Arizona shows rancher George Alan Kelly. (Santa Cruz County Police Department via AP, file)

An Arizona rancher accused of killing a Mexican on his property near the US-Mexico border while allegedly shooting a group of unarmed immigrants is facing a misdemeanor charge of manslaughter.

George Alan Kelly’s attorney pleaded not guilty to manslaughter on Friday in Santa Cruz County Court in Nogales, Ariz., during an evidence hearing.

Kelly was originally charged with manslaughter, but prosecutors amended their criminal complaint on Thursday. He also faces two counts of aggravated assault.

Kelly’s attorney, Brenna Larkin, requested a postponement of the hearing to prepare for the new charge, but Justice of the Peace Emilio G. Velasquez denied her request.

The hearing is also intended to determine material factual issues in the case and allow Kelly’s defense to call witnesses.

The case sparked a lively political debate on border security.

Prosecutors allege Kelly, 74, opened fire with an AK-47 rifle on about eight unarmed immigrants he met on January 30 at his ranch outside Nogales, hitting the man in the back who died while I was trying to escape. Two of the migrants told authorities that Kelly also shot them, but they were unharmed and returned to Mexico over a fence.

Prosecutors say the 48-year-old migrant who was killed lived just south of the border in Nogales, Mexico. He is only mentioned in court documents by his initials, but Santa Cruz County police say his name was Gabriel Cuen Buitimea. US court records show Cuen had multiple convictions for illegally entering the United States and deporting to Mexico, most recently in 2016.

Kelly also faces two counts of aggravated assault against the two immigrants who came forward and said they would testify in the case. Prosecutors noted that although the two men were not assaulted, one said they “felt like they were being stalked.”

Kimberly Hunley, the county’s deputy chief attorney, said her office, the court and the police department “have received disturbing information, some of a threatening nature, which appears to indicate an ongoing threat to the safety of victims.”

Categorized in: